250 •' MORPHOLOGY AND EVOLUTION to the rectum. The superior mesenteric vein drains the ileum, jejunum and large intestine from the appendix to the hepatic flexure. It receives gastric (g.v.) and duodenal (d.v.- veins.'" C.v LESSER CURVE FUNDUS, dv FIG. 4:6.—The portal vein in the Chimpanzee, c.v., cystic vein; d.v., duodenal vein; g.v., gastric vein. Other letters explained in text. The transverse colon is drained by the vein (T.M.C.V.) which connects the mesenteric systems. Inferior Caval System.*—The vena cava inferior has the same formation, course and relations in the higher Apes as in iJ an, but it may be divided for a considerable part of its course in the Gibbons. The tributaries are much as in Man. * Wittmann (299) has dealt with the portal vein, Keith (196) with the inferior vena cava, and Giacomini (67) with the veins of the leg.